This happens only at the open of a document or book. And it stays there when all documents/books are closed and only the Welcome screen is present.
The problem seems to be specific to the top menus, because changes to the existing menu structure (added items in Help and elsewhere) are present already in the menus presented at Welcome screen stage. And in these changes also Order statements are involved.
Somebody had placed a more detailed sequence of FM startup things on the web, but I do not find it again - probably due to the remake of the Adobe forums.
→ Can anybody give me a tip how to get the correct appearance of the top menu even at the very start?